The present disclosure relates generally to Vernier-type electro-dynamic machines and similar electrical machines. Vernier-type machines may utilize magnetic flux harmonics to transfer energy between a stationary component and a movable component. Such machines are known to be suitable for certain low speed and high torque applications. Existing systems suffer from a variety of drawbacks, shortcomings and disadvantages. There remains a significant unmet need for the unique apparatuses, methods and systems disclosed herein.